1. Field of the Invention
The present invention relates to an image forming apparatus such as a digital copying machine, a multifunction machine, and a printer, and more particularly to use of public key infrastructure (PKI) in an imaging forming apparatus.
2. Description of Related Art
In public key infrastructure, a private key of a user is very important to the user and must therefore be managed strictly. A private key is commonly installed in a personal computer or in an IC card.
In recent years, use of the public key infrastructure technology in image forming apparatuses such as a printer has also been proposed and promoted. Because it is often the case that an image forming apparatus is shared by a great number of people in an office or other circumstances, configurations in which each user carries their private key or the like by means of an IC card, which is to be set in a card reader attached to the imaging forming apparatus in order to use the image forming apparatus, have been considered.
However, providing an IC card reader to an image forming apparatus represents a considerable expense. Accordingly, there has been strong demand for a structure which enables each user to use their private key in an image forming apparatus in a less expensive manner.
Japanese Patent Laid-Open Publication No. 2004-147019 discloses a system in which an applicant receives, via facsimile, a certificate sheet having bar code data indicating a key pair (a private key and a public key) and the content of a public key certificate printed thereon from a server, and the recipient then uses the private key on the certificate sheet or the like to perform a process such as digital signing or the like.
A system in which a private key, a public key, or the like are printed on a sheet as disclosed in Japanese Patent Laid-Open Publication No. 2004-147019 is advantageous in that, because the system does not require a device for reading IC cards, an image forming apparatus, which is essentially provided with a printing function and a document reading function, requires substantially no additional hardware in order.
This system, however, has a risk that a certificate sheet having the private key or the like printed thereon is more easily copied and the key is used in an unauthorized manner.